It is well known to provide a lamp assembly comprising a light source, such as an incandescent bulb, which emits light in a multitude of directions, and a reflector positioned adjacent the source to direct light emitted rearwardly from the source in a forward direction. The object is to make use of as much as possible of the light energy emitted by the source. The problem which arises, however, is that the light source itself is in the path of some of the light reflected by the reflector and thus prevents that light from being usefully employed. With a view to solving the above problem, it is known to provide a lamp comprising an incandescent bulb including a filament formed with a number of spaced apart parallel segments and a spherical mirror arranged for reflecting light through the gaps between the segments. However, practical difficulties are involved in implementing this proposal since a filament of this structure is somewhat mechanically unstable and the tolerances required to implement this reliably difficult to achieve.